Neurology Flashcards
What are the clinical features of PRES (posterior reversible encephalopathy syndrome)? Aetiologies? Which other name does it go by?
Features: headache, confusion, seizures and visual loss
Aetiology: malignant HTN, pre-eclampsia
AKA: Reversible posterior leucoencephalopathy
Give causes of small pupils.
Causes of SMALL pupil (AHA-POO)
Argyll-Robertson pupil (neurosyphilis / DM) Horner’s syndrome Age Pontine CVA Opioids Organophosphates
Give causes for dilated pupils.
Causes for dilated pupils
“CHEAT and you die!”
Carbon monoxide - SUICIDE Holmes-Adie pupil – post-infective damage to post-ganglionic ANS/PSNS Ethylene glycol - SUICIDE Atropine Third nerve palsy
What is Miller-Fisher syndrome? How is it diagnosed (triad and blood test)?
Miller Fisher syndrome:
- Variant of GBS
- Post-infective triad (AOA): areflexia, ophthalmoplegia, ataxia
- Ix: GQib (ganglioside IgG Ab) – 95% specific
What are anti-purkinje Abs?
Anti-pukinje cell Abs detect
- subacute cerebellar degeneration
- autoimmune peripheral neuropathy from breast/gynae carcinoma
What is Refsum’s disease? How is it treated?
Genetic cause of demyelination.
Autosomal recessive disorder that leads to phytanic acid oxidase deficiency causing a build-up of phytanic acid and demyelinating polyneuropathy.
Rx: phytanic acid restricted diet - avoid fats from animals/fish.
What is Lewis-Sumner syndrome?
Asymmetric variant of CIDP (chronic inflammatory demyelinating polyneuropathy).
Give 7 causes of demyelinating polyneuropathy.
Immunology-related (3):
Guillain-Barre Syndrome
CIDP (or Lewis-Sumner if asymmetric)
HIV
Genetic (2):
Hereditary motor sensory neuropathy
Refsum’s disease
Drug (1): Amiodarone
Cancer (1): Paraproteinaemia
Give 4 causes of axonal polyneuropathy.
DAVV: DM Alcohol Vasculitis Vitamin deficiency
Regarding nystagmus, which phase (slow vs. fast) defines the direction of the nystagmus?
Fast phase.
What are the 4 main causes of nystagmus (consider anatomy)?
- Visual disturbance
- Labyrinth lesion
- Vestibular lesion
- Brainstem/cerebellar lesion
What is anisocoria?
Unequal pupils. Normal in 20% of population but may reflect a benign or serious condition.
In a case of anisocoria, how does one determine which pupil is abnormal?
The abnormal pupil can be identified by examination in light and dark conditions.
Anisocoria that is greater in the DARK identifies the SMALL pupil as abnormal and implies a lesion in the SYMPATHETIC pathways e.g. Horner’s syndrome (AHA-POO causes of small pupil)
Anisocoria that is more pronounced in LIGHT conditions identifies the LARGE pupil as abnormal and implies a lesion in the PARASYMPATHETIC pathways e.g. Holmes-Adie pupil (CHEAT causes of dilated pupil)
True/False: Marcus-Gunn pupil causes anisocoria.
False.
Marcus-Gunn pupil is NOT associated with unequal pupils
What is a Marcus-Gunn pupil and what is it usually due to?
Relative afferent pupillary defect suggest lesion to optic nerve or retina (i.e. afferent pupillary pathway). Abnormal eye paradoxically dilates to light exposure.
Lesion in optic nerve is between retina and optic chiasm.
Describe the 2 neurotransmitters of the autonomic nervous system (ANS = SNS / PSNS).
Ach: secreted by all neurons of the ANS, except the post-ganglionic neurons of SNS.
Norad (and some Adr): secreted by post-ganglionic neurons of SNS.
What are the 3 main sites that catecholamines are produced in the body?
- Post-ganglionic neurons of SNS
- CNS
- Adrenal medulla (chromaffin cells)
What autonomic system structure is the adrenal medulla analogous to?
Why does it produce more adrenalin than noradrenalin?
Adrenal medulla = post-ganglionic neuron of SNS.
Glucocorticoids from the adrenal cortex promotes increased levels of PNMT (phenylethanolamine-N-methyl transferase) which converts noradrenalin to adrenalin.
What spinal lesion would cause weakness of finger flexion?
Spinal lesion at level C8
Brachioradialis (supinator reflex) is mediated by which spinal level?
C5/C6
I was told a fantastic mnemonic for REFLEXES that went like ‘1,2,3,4,5,6,7,8’
WTF?
From inferior to superior:
1,2,
3,4,
5,6,
7,8
S1,S2 = ankle jerk
L3, L4 = knee jerk
C5, C6 = biceps
C7, C8 = triceps
I was told another awesome mnemonic for REFLEXES that went like ‘1-2 buckle my shoe, 3-4 kick the door, 5-6 pick-up sticks, 7-8 lay them straight’
S1,S2 = ankle jerk (shoe = ‘s’)
L3, L4 = knee jerk
C5, C6 = biceps
C7, C8 = triceps
Mnemonic for upper limb peripheral nerve palsies?
DR CUMA:
Dropped wrist
Radial nerve palsy
Claw hand or ‘hand of benediction’ (flexion of 4th + 5th digit)
Ulnar nerve palsy
Median nervel palsy
Ape hand - loss of thumb abduction
The ‘OK’ sign with the hand test motor function of all three nerves of the hand, how?
Radial nerve palsy = inability to dorsiflex the hand (wrist drop)
Ulnar nerve: inability to abduct 4th and 5th ulnar digits (claw hand)
Median nerve palsy = inability to abduct thumb (ape hand)
True/False: brief episode of neurological deficit that last < 24 associated with brain injury on imaging is considered a TIA.
False: not according to the new definition of TIA.
True/False: stroke is often associated with LOC and/or confusion.
False.
Stroke mimics are suggested if:
- known cognitive impairment
- LOC/seizure at onset
- Patient able to walk with no lateralising symptoms
- Confusion and NO neurological symptoms
Which of the following interventions for ICH has evidence to suggest benefit:
- Surgery / clot evacuation
- Lower BP to < 140/90
- Transexamic acid
- Stroke unit
Only stroke units yield demonstrable benefit
For a large hemispheric stroke, grade the following in terms of greatest RRR to least:
- Stroke unit
- tPA
- Hemicraniectomy
- Aspirin
Greatest RRR
Hemicraniectomy
tPA
Stroke unit
Aspirin
Least RRR
NB: patient may survive hemicraniectomy but QoL may be poor!
What are the cascade of neurological deficits associated with B12 deficiency?
Peripheral neuropathy THEN
Loss of vibration and position sense THEN
Areflexia and weakness THEN
Spasticity with extensor babinskis +/- ataxia
What is Neuralgic Amyotrophy?
Upper plexopathy that is usually post-infective.
Initially with days to weeks of pain then weakness and sensory loss correlating to C5-7 territory.
Self limiting condition (may take years).
What is the triad for normal pressure hydrocephalus?
3Ws (wet, wobbly and wacky):
- Urinary incontinence
- Ataxia
- Confusion / memory impairment
What is Syringomyelia?
Fluid filled cavity (syrinx) in the spinal cord (often cervical spine - C2-C9) that elongates and enlarges causing compression of:
- Corticospinal tract (ipsilateral motor)
- Spinothalamic tract (contralateral pain and temperature)
- Anterior horn cells
What are the clinical features of Syringomyelia?
Headaches
Motor deficit (CsT): ascending weakness/wastig of hands then forearms then shoulders
Bladder symptoms
Absent reflexes
Central cord deficit (sensory loss in pain and temperature (StT), then light tough and propioception)
What is Syringobulbia?
What is it often associated with?
What population is it more common in?
Synrinx extends into brainstem that is often associated with a Chiari malformation that impairs CSF circulation.
More common in men in 20-30s.
How is syringomyelia or synringobulbia treated?
What investigation should NOT be done?
Early surgical decompression with shunt insertion.
Do NOT do a lumbar puncture.
What clinical features distinguish an L5 radiculopathy from a common peroneal nerve lesion (4)?
L5 innervates everything the common peroneal nerve does PLUS tibialis posterior + gluteal muscles.
‘Knowing this makes you to look FLASH! (L for L5)
Foot inversion lost
Ankle reflex lost
Sensory loss (dorsum of foot and lateral leg)
Hip abduction and internal rotation lost
Match the following epic list of antibodies to their conditions:
Anti-NMO Anti-GQ1b Anti-GM1 Anti-MAG Anti-ACh receptor Anti-MuSK
Anti-NMO = Devic’s disease
Remember: Anti-NEMO… you must be a DEVIL!
Anti-GQ1b = Miller Fischer
Remember: Dr Fischer does not like GQ magazine!
Anti-GM1 = Multifocal Motor Meuropathy (MMN)
Remember: Good Morning grandpa! Time to put on your MULTIFOCAL glasses to start the day.
Anti-MAG = Waldenstroms or Distal Acquired Demyelinating Symmetric (DADS) Polyneuropathy (distal sensory loss)
Remember: Cool MAGS are for DADS that are not WALLflowers!
Anti-ACh receptor = Myasthenia Gravis (MG)
Anti-MuSK = MG with respiratory distress and bulbar involvement (less eye involvement)
Remember: This MUSKy smell burns my throat and lungs!
What is the presentation of Multifocal Motor Neuropathy (MMN)?
How is it treated?
MMN present with LMN deficit arm > legs
Responds to steroids and IVIG.
What condition is Devic’s disease similar to?
How do they present?
Similar to multiple sclerosis
Except there are NO oligoclonal bands in the CSF, with predominance of PMN in CSF.
Presents with vomiting and painful optic neuritis.
Patient presents with Anti-MAG in blood and distal sensory loss. Diagnosis?
Distal Acquired Demyelinating Symmetric (DADS) Polyneuropathy
Patient presents with symptoms similar to Myasthenia Gravis with sparing of the eyes and SOB. Bloods reveal Anti-MUsK antibodies. Diagnosis?
Seronegative MG
What is Lamber-Eaton myasthenic syndrome (LEMS)?
Rare autoimmune disorder characterised by weakness in the limbs due to Abs to presynaptic voltage-gated calcium channels
Often associated with malignancy (e.g. SCLC) and is considered a paraneoplastic syndrome.
What part of the brain is implicated with a SEMANTIC memory deficit?
How might you test this?
Test: ask patient to differentiate different animals.
Left (DOMINANT) lateral temporal lobe.
What are the clinical features of a frontal lobe lesion?
Perseveration
and
REDUCED: attention / memory calculation / planning activity / spontaneous activity concern (loss on inhibition)
Patient presents with a ‘pure’ sensory or motor stroke, where is the lesion?
What is the prognosis?
Lacunar stroke - discrete lesion in the contralateral PONS or INTERNAL CAPSULE.
Good prognosis
Patient present with dysarthria and clumsy hand syndrome, where is the lesion?
Contralateral pons.
Name 6 drugs that may cause DEMYELINATING neuropathy.
PPATTC (Patsy!)
Procainamide Perhexeline Amiodarone TNFi Tacrolimus Chloroquine
Name 3 drugs that cause AXONAL neuropathy,
VET:
Vinca-alkaloids
EtOH
Thalidomide
What is Gerstmann syndrome?
Stroke of the dominant parietal lobe:
- Alexia (cannot write)
- Acalculia
- Finger agnosia
- Right-left disorientation
What is the consequence of a stroke to PICA?
Lateral Medullary Syndrome / Wallenberg:
- ipsilateral loss of pain and temp in face
- contralateral loss of pain and temp in body
- Vertigo / dysphagia / dizziness / ataxia / nystagmus
What is Weber’s syndrome?
PCA lesion:
- Ipsilateral CNIII lesion
- Contralateral weakness
What are the CNs that subserve the corneal reflex?
Sensation (afferent) = CNV
Motor (efferent) = CNVII
What are the characteristic findings of motor neuron disease?
LMN deficit in upper limbs and UMN deficit in the lower limbs.
UMN (everything goes up): reflexes, tone, plantars
LMN (down): refelexes, tone, plantars
What are the side effects of phenytoin (mnemonic = PHENYTOIN)
PHENYTOIN:
P: P-450 interactions H: Hirsutism E: Enlarged gums N: Nystagmus Y: Yellow-browning of skin T: Teratogenicity O: Osteomalacia I: Interference with folic acid absorption (hence anemia) N: Neuropathies: vertigo, ataxia, headache
